Habitat use of Pacific herring (Clupea pallasii) in Prince William Sound, Alaska

Abstract

To determine the spawning area contributions of Pacific herring (Clupea pallashii) larvae to nursery bays, otolith chemical analysis was conducted on juvenile fish collected from 1995 to 1997 in Prince William Sound, Alaska. The otolith edge, representing the chemical signature of the known capture location, and the otolith core, representing the unknown spawning ground chemistry, were compared with discriminant function analysis to infer spawning area origin. Chemical signatures of ⁸⁷Sr/⁸⁶Sr, ⁸⁸Sr/⁴⁸Ca, ²⁴Mg/⁴⁸Ca, and ¹³⁸Ba/⁴⁸Ca were used to identify broad spawning regions from inner and outer PWS that persisted for the three years sampling period despite significant interannual variability in otolith edge chemistry within nursery bays. Age of juvenile Pacific herring, age-0, 1, 2, did not significantly affect the otolith edge signatures; thus, this study is able to conclude from the otolith core chemistry that spawning areas do not contribute equally to nursery bays. This is the first demonstration that otolith chemical signatures can be used to identify the important spawning areas of this commercially important species in the Gulf of Alaska coastal areas.